It also helps to insulate the house and block the sunlight from the outside of the window. If you only use curtains, all the heat still get inside the house. N

It also helps to insulate the house and block the sunlight from the outside of the window. If you only use curtains, all the heat still get inside the house. Norwegian company buildings are not allowed to install AC if you don’t have outside sunscreening. This is to save energy used by AC.